Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

Câu hỏi

Environmentalists are earnestly trying to determine ________ of the ozone layer over the poles.

A. what is causing the deterioration

B. what the cause of the deterioration

C. is causing the deterioration

D. the deterioration is causing

Đề thi thử tiếng Anh THPT Quốc gia 2023 (Mã đề 002)